The present invention relates generally to an inserting machine for mass mailing and, more specifically, a device to cause a large number of separate cut sheets to be accumulated into individual stacks each having a number of sheets.
Multi-station document inserting systems are generally used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mailpiece are directed to a particular addressee. One of the most important features of the inserting systems is speed, which is measured by the number of mailpieces that can be assembled in a given time period. A modern inserting system is expected to assemble over ten thousand mailpieces per hour. A typical inserting system includes a plurality of serially arranged stations including a sheet feeding station, a folding station and an insertion station. In general, the sheet feeder feeds one or a plurality of sheets of mailing materials to an accumulator, which collects the fed sheets into a predefined collated packet or stack. Mailing materials are usually printed on a continuous web of paper and the printed paper is cut into individual sheets. These sheets are then accumulated into individual stacks and each stack is stuffed into an envelope for mailing. One of the conventional ways of sheet accumulation is to slow down or stop the sheets in an impending accumulation (i.e., for a mailpiece) at a certain point until all the sheets have arrived. This conventional method is cumbersome and inefficient because it requires a drastic change in machine speed.
As disclosed in related patent application Ser. No 09/310,217, now issued as U.S. Pat. No. 6,273,419 sheets 1001, 1002, 1003 are accumulated in an apparatus 1, which has a plurality of paths 211, 212, 213, . . . , connecting the entry point 2 and the exit point 4, with each path having a different pathlength. Related U.S. Pat. No. 6,273,419 in hereby expressly incorporated by reference. The paths are so controlled that, for each stack of the sheets in an impending accumulation, a sheet entering the accumulator will travel a progressively shorter path than the preceding one. In other words, the first sheet travels a longer path than the second sheet, the second sheet travels a longer path than the third sheet, and so forth. The pathlength difference between two successive paths can be designed in accordance with the requirement in sheet stacking. If the sheets are stacked in a way that one sheet is partially overlapped with another, like the shingle pattern on a rooftop (see stack 110, FIG. 1), then the pathlength difference between two successive paths is smaller than the length of the sheets. If the edges of the accumulated sheets in a stack are flush with each other, then the pathlength difference is substantially equal to the sheet length. For example, if only three sheets 1001, 1002, 1003 are to be accumulated into a stack 110, then sheets 1001 1002, 1003 are separately directed to paths 213, 212 and 211, respectively, as shown in FIG. 2. As shown in FIG. 2, when the sheets to be accumulated enter the entry point 2 along a path 200, they are caused to change direction so that they can be separately directed toward different paths. As shown, the direction of incoming sheets is changed from 200 to 202. After being accumulated, the stacked sheets are moved along path 218 and they are again caused to change direction to path 220 before exiting through the exit point 4.
As sheets are moved in high speed in and out of the accumulating apparatus 1, jams could occasionally occur. It is advantageous and desirable to provide a way to clear the jam.
It is an object of the present invention to provide an apparatus for sheet accumulation, wherein the sheets to be accumulated are not required to slow down significantly or pause in the accumulation process.
It is another object of the present invention to provide an apparatus for sheet accumulation, wherein the apparatus can have a small footprint.
It is yet another object of the present invention to provide an apparatus for sheet accumulation, which has a turnbar to change the direction of the sheets to be accumulated when the sheets are separately entering the accumulation apparatus, and the direction of the accumulated stack when the stack exits the accumulation apparatus. As such, the sheets prior to accumulation and the accumulated stack travel in the same direction. According to the present invention, the turnbar can be removed from the accumulation apparatus for jam clearance and maintenance purposes.
Accordingly, the first aspect of the present invention is a sheet accumulator, which comprises:
an accumulating assembly that accumulates a plurality of sheets that serially and separately enter an entry point so as to allow these sheets to overlap each other thereby forming a stack at an exit point, the accumulator having a plurality of paths connecting the entry point and the exit point with each path having a different path length, and means for controlling the paths so as to allow each sheet of said plurality of sheets to travel a different path such that a sheet entering the entry point travels a shorter path than a preceding sheet, wherein the sheets travel along a first direction prior to entering the entry point, a second direction different from the first direction after entering the entry point, a third direction different from the second direction prior to leaving the exit point, and a fourth direction different from the third direction after leaving the exit point;
a removable turnbar having first means located in the proximity of the entry point for directing the sheets entering the entry points from the first direction to the second direction, and second means located in the proximity of the exit point for directing the sheets leaving the exit point from the third direction to the fourth direction.
Preferably, the turnbar is operable at a first position and a second position, and wherein when the turnbar is operated at the first position, the turnbar is engaged with the accumulating assembly for directing the sheets entering the entry point from the first direction to the second direction and for directing the sheets leaving the exit point from the third direction to the fourth direction, and when the turnbar is operated at the second position, the turnbar is disengaged from the accumulating assembly to facilitate maintenance and/or jam clearance of the sheet accumulator.
Preferably, the sheet accumulator further comprises a securing mechanism to prevent the turnbar from being disengaged from the accumulating assembly when the turnbar is operated at the first position, wherein the security mechanism comprises a pin on the turnbar which is engaged with a latch on the accumulating assembly.
Preferably, the sheet accumulator further comprises a securing mechanism to prevent the turnbar from accidentally engaging with the accumulating assembly when the turnbar is operated in the second position, wherein the security mechanism comprises a pin on the turnbar which is engaged with a latch on the accumulating assembly.
The second aspect of the present invention is a turnbar for use in a sheet accumulator having an accumulating assembly, wherein the accumulating assembly accumulates a plurality of sheets that serially and separately enter an entry point so as to allow these sheets to overlap each other and thereby form a stack at an exit point, the accumulator having a plurality of paths connecting the entry point and the exit point with each path having a different path length, and means for controlling the paths so as to allow each sheet of said plurality of sheets to travel a different path such that a sheet entering the entry point travels a shorter path than a preceding sheet, wherein the sheets travel along:
a first direction prior to entering the entry point;
a second direction different from the first direction after entering the entry point;
a third direction different from the second direction prior to leaving the exit point; and
a fourth direction different from the third direction after leaving the exit point. The turnbar comprises:
a first means located in the proximity of the entry point for directing the sheets entering the entry point from the first direction to the second direction;
a second means located in the proximity of the exit point for directing the sheets leaving the exit point from the third direction to the fourth direction; and
a mounting mechanism for removably mounting the turnbar on the sheet accumulator.
According to the present invention, the sheets are capable of leaving the exit point along the fourth direction in a first exit path or a second exit path, and the turnbar further comprises a path diverting mechanism for selecting either the first or the second path.
According to the present invention, the turnbar further comprises a center bar located between a first side arm and a second side arm, wherein the first side arm has a first surface substantially parallel to the first direction for guiding the sheets to move toward the entry point, the second side arm has a second surface substantially parallel to the fourth direction for guiding the sheets to move away from the exit point, the center bar has a third surface substantially parallel to the second direction for guiding the sheets to move toward the accumulating assembly in the second direction and a fourth surface substantially parallel to the third direction for guiding the sheets to move toward the exit point in the third direction.
According to the present invention, the first means may comprise a curved surface located between the first surface and the third surface for urging the sheets to move from the first direction to the second direction, and the second means may comprise a curved surface located between the second surface and the fourth surface for urging the sheets to move from the third direction to the fourth direction.
According to the present invention, the sheets are capable of leaving the exit point along the fourth direction in a first exit path along the second surface or a second path spaced from the second surface, and wherein the turnbar further comprises a path diverting mechanism for selecting either the first or the second path.
According to the present invention, the path diverting mechanism comprises a flipper operable at a first position to allow the sheets to reach the second curved surface and a second position protruding into the third direction to cause the sheets to move toward the second path.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 3 to 6b. 